Install Manual

Preliminary
SKY899
Installation Manual
2-2
Rev. A
2.3 ANTENNA LOCATION
Location is an important factor for maximum antenna performance. Optimum location for a particular
aircraft type is usually available from the aircraft manufacturer. In selecting a location, consider the
following:
Directional Antenna The mounting site should be on the top forward fuselage, as close to the
centerline as possible, and within -10° of the in-flight horizon (see figure 2-1).
The optimum mounting point for maximum coverage is as far forward as
possible without exceeding the -10° forward pitch. If necessary, consideration
should be given to relocating other antennas to obtain the furthest forward
location for the directional antenna. The antenna should be mounted on the
aircraft with at least 20 dB isolation (about 30 inches (76.2 cm)) from other L-
band frequency antennas and 24 inches (61.0 cm) from other antennas or
obstructions. The ground-plane should be as large as possible, a 30-inch (76.2
cm) ground-plane diameter is recommended.
The directional antenna can be bottom mounted only if a suitable top mount
location is not available. Each bottom mount installation must be evaluated on
a case-by-case basis. Before starting a bottom mount installation, contact Field
Service Engineering at 1-800-453-0288 or 1-616-949-6600.
Figure 2-1. Directional Antenna Mounting Location
2.4 TRC LOCATION
Typically the TRC is installed in the electronics bay. In selecting a location, consider the following:
Cable Length Cable runs should be as short as practicable in order to minimize potential
electrical interference. Cable length to antennas must not exceed the values listed
in table 1-6.
Cooling While the TRC has no special cooling requirements, it should be mounted to permit
adequate ventilation. Caution should be observed to not inhibit airflow from the
rear mounted fan. Allow at least three inches (8 cm) of rear clearance.
Pressurized Aircraft The TRC may mount inside or outside the pressure vessel. The TRC contains no
batteries or potentially explosive components and will operate up to 55,000 ft.